The European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5) and hourly observation data of wind direction and speed at meteorological stations from March 2018 to February 2021 are adopted to investigate the characteristics of the sea-land breeze over Tianjin coastal area. Firstly, conventional methods are used to identify the sea-land breeze events over Tianjin coastal area. Secondly, the interannual average and seasonal differences of sea-land breeze characteristics, such as the starting and ending time, duration and intensity, are analyzed and compared based on these two sets of data with the purpose to make an assessment of the applicability of ERA5 data. Similarities and differences are concluded as follows. (1) Both data are capable of revealing the fact that sea-land breeze events mostly occur in summer with similar distributions in all 4 seasons. The sea breeze lasts longer than the land breeze with stronger intensity. Both breezes reach their maximum intensities in spring. (2) There are interannual differences revealed by these two sets of data. Compared to results revealed by ERA5 data, the starting and ending time of the sea breeze revealed by the observation data have a weaker bimodal structure. The observed starting and ending time of the land breeze are ahead of their correspondences revealed by ERA5 data. The durations of both the sea breeze and the land breeze are shorter revealed by the observation data. (3) There are also seasonal differences. The minimum intensity of the land breeze revealed by ERA5 data appears in summer and the longest duration of the sea breeze appears in autumn. However, the minimum intensity of the land breeze revealed by the observation data appears in autumn and the longest duration of the sea breeze is in spring and summer. The assessment indicates that ERA5 data with the duration of three years, highly correlated with the observation data, are suitable for analyzing the sea-land breeze over Tianjin coastal area.